CN101015003A - Magnetic recording medium and production process thereof - Google Patents
Magnetic recording medium and production process thereof Download PDFInfo
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- CN101015003A CN101015003A CN 200580027949 CN200580027949A CN101015003A CN 101015003 A CN101015003 A CN 101015003A CN 200580027949 CN200580027949 CN 200580027949 CN 200580027949 A CN200580027949 A CN 200580027949A CN 101015003 A CN101015003 A CN 101015003A
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Abstract
The present invention provides a magnetic recording medium having superior startup operation and durability as well as satisfactory surface lubricity. The present invention relates to a production process of a magnetic recording medium in which at least a magnetic layer, a protective film layer and a lubricant layer are sequentially laminated on a non-magnetic substrate, wherein the protective film layer is surface treated using a gas activated by plasma generated at a pressure in the vicinity of atmospheric pressure. The present invention also relates to a magnetic recording medium produced according to the aforementioned production process.
Description
Technical field
The present invention relates to used a kind of magnetic recording media and manufacturing process thereof in disc driver or other magnetic recording device.
Background technology
Hard disk drive is a kind of magnetic recording device as memory devices such as information processing devices, and magnetic head that is used for playback and record and the magnetic recording media that provides with the form that contains magnetospheric disk are provided for it.Described magnetosphere in the disk is by depositing one deck feeromagnetic metal with sputter, vapour deposition or electroless plating or the like method or its alloy forms on non-magnetic substrate.Usually, (contact start stop, CSS) method writes down and playback of data to adopt a kind of so-called contact start and stop in hard disk drive.In the hard disk drive that uses the CSS method, magnetic head contacts with magnetic disk (abbreviating disk as) when starting working, when disk begins to rotate, magnetic head slides on disk, when the disk velocity of rotation increased, magnetic head just lifted from disk, write down in this state and playback.When stopping, magnetic head begins again to slide on disk when the velocity of rotation of disk reduces.
In disk; for the permanance that prevents disk owing to the friction damage that is produced with the magnetic head sliding contact is degenerated, static friction and kinetic friction when on magnetosphere, applying layer protecting film layer and one deck lubricating layer and improving the abrasion resistance of disk and reduce magnetic head and disk sliding contact.Usually use carbon film, SiO
2, ZrO
2And other oxidation film, nitride film and boride film are as aforesaid protective film.
In addition, aforesaid lubricant layer normally forms by the lubricant that is coated with one deck such as liquid per-fluoro polyether compound (perfluoropolyether) at magnetic disk surface.
In disk, number and characteristic with the molecule of diaphragm surface bond in molecule that moves freely in the lubricant layer and the lubricant layer have material impact for abrasion resistance.For example, if the quantity of the molecule that moves freely in the lubricating layer is too many, the coefficient of static friction of disk will increase, and causes adsorption phenomena between magnetic head and the disk (so-called stickup, being more prone to stiction).If quantity very little, the coefficient of sliding friction of magnetic disk surface increases, and causes lubricity to reduce, make being more prone to that magnetic head falls.
In order to reduce to paste, have to a certain degree the roughening that is called as veining by making magnetic disk surface, perhaps form the small embossment that is known as laser texture by giving with laser emission, reduce the contact area between magnetic head and the disk.Magnetic head becomes very low in the flying height of magnetic disk surface, is 25nm or lower, so that obtain higher recording density yet recently.Therefore, need make magnetic disk surface smooth as far as possible, and reduce the height of the projection that forms by laser-graining, contacting between disk and magnetic head when avoiding beginning to drive.Yet after doing like this, adhibit quality degenerates on the contrary.Because adhibit quality can not only reduce by the projection that is formed by laser-graining fully, also need to control the number and the characteristic that move freely in the lubricating layer in molecule and the lubricating layer with the molecule of protective film surface bond, as previously described.
Along with the increase of recording density, require the bond strength of lubricating layer enhancing and protective film.The reason of this demand is as described below.By using MR element, GMR element or the like magnetic head to improve recording density, it is more and more compacter and light that hard disk drive is just becoming, and require to improve start-up operation by reducing coefficient of static friction so that reduce the initial driving power that also constitutes head load.In order to reduce coefficient of static friction, it is effectively reducing the number that moves freely molecule in the lubricating layer by the bond strength between increase lubricant and the protective film.
Except CSS (contact start and stop) method, also use ramp load method (rampload method) recently in practice.Ramp load method refers to a kind of like this method, and it uses a kind of mechanism, by this mechanism, provides a magnetic head to withdraw from the district near the periphery of disk, and when the disk rotation stopped, magnetic head can be docked in this and withdraw from the district.In this method because disk when static magnetic head do not contact with disk, allegedly needn't as the CSS method, worry the stickup problem.Yet determined, in ramp load method, also needed to reduce the absorption of magnetic head, the behavior variation of minimizing magnetic head when contact carelessly between convenient magnetic head and disk to disk.Therefore, it also is very important reducing coefficient of static friction in ramp load method.
In addition, in order to increase recording density, the velocity of rotation of disk has increased during record and playback.In the situation that increases velocity of rotation, a kind of so-called spin-off (revolve and fly) phenomenon can take place, wherein outwards splash owing to the action of centrifugal force lubricant.As a result, the problem that reduces of lubricating layer thickness will take place.Therefore also wish the bond strength of increase and protective film, fly phenomenon, strengthen durability so that prevent to revolve.In addition, liken indication to bonding into bond strength between lubricant and the protective film.This value indicates the disk that is formed with lubricant layer in the above and (for example uses fluorine-based solvent; Asahi Glass Co.; Ltd. the ratio (%) of the residual lubricant in the flushing back AS225 of Sheng Chaning), and provide a general reference for the bond strength between lubricant and protective film.
So, on lubricant layer, attempted various disposal routes, so that strengthen the bond strength between lubricant layer and the protective film.For example,, announced a kind of method among the publication number No.H11-25452, wherein, on lubricant coating, heat-treated, and then carry out treatment with uv radiation in the Japanese laid-open patent application.In addition,, announced a kind of method among the publication number No.H8-124142, wherein, formed behind the lubricant layer with wavelength at 150 to 180nm ultraviolet radiation lubricant layer in the Japanese laid-open patent application.In addition, in the Japanese laid-open patent application, announced a kind of method among the publication number No.H7-85461, wherein, lubricant layer is painted on the carbon protective film of a hydrogenation, carries out ultraviolet radiation then.In addition, in the Japanese laid-open patent application, announced a kind of method among the publication number No.H5-217162, wherein, lubricant is painted on the carbon protective film, heat-treats then.In addition,, announced a kind of method among the publication number No.S62-150526, wherein, on carbon protective film, carried out Cement Composite Treated by Plasma in the Japanese laid-open patent application.
Yet; prior art is in production process of magnetic recording media; wherein lubricant layer and diaphragm adopt these disposal routes to form, and are difficult to make a kind of magnetic recording media that can strengthen the bond strength between lubricant layer and the protective film and don't increase the coefficient of sliding friction.So, needing a kind of like this magnetic recording media, it has remarkable startability and durability and has enough surface lubrications simultaneously.
In addition, except above-mentioned target, magnetic recording media also requires to indicate the durability about anticorrosive aspect.
Used non-magnetic substrate is mainly used in the Al substrate and containing the substrate that is electroplate with NiP on the substrate of glass of Li and Na in magnetic recording media.In addition, Co base alloy is used to magnetosphere.If thin diaphragm is arranged, Ni, Li, Na and Co can not be deposited on the surface of magnetic recording media.Yet, if diaphragm is thinless or have pitting to form, can form oxide and oxyhydroxide at elements such as these positions Ni, Li, Na and Co so, these element depositions are on the surface of magnetic recording media as a result.This is known as corrosion.
Although corrosion takes place with various forms, it highly usually surpasses 25nm.The height of corrosion is generally 100 to 10000nm.Therefore, if corrosion has taken place, magnetic head will collide with corrosion, causes magnetic head to fall.
Consider above-mentioned situation, target of the present invention is, obtains a kind of magnetic recording media, and it has remarkable startability and durability, gratifying surface lubrication and remarkable corrosive property are arranged.
Summary of the invention
Result as the broad research of carrying out in order to address the above problem; the present inventor finds; in manufacturing process; wherein protective film is being carried out surface treatment near the processing gas that glow discharge plasma activated that produces under the atmospheric air pressure; by using sinusoidal wave high frequency electric source as the power supply that produces described plasma; not only can strengthen the bond strength between lubricant and the protective film; reduce coefficient of static friction; improve start-up operation; strengthen durability and obtain remarkable surface lubrication; and can improve corrosive property, therefore caused of the present invention finishing.
In other words, the present invention adopts following article to realize above-mentioned target.
(1) a kind of manufacturing process of magnetic recording media, be included on the non-magnetic substrate sequential cascade one deck magnetosphere, layer protecting film layer and one deck lubricating layer at least, and come described protective film is carried out surface treatment with the gas that plasma activated that produces down near an atmospheric air pressure; Wherein, use sinusoidal wave high frequency electric source as the power supply that produces described plasma.
(2) as the manufacturing process of the magnetic recording media described in above-mentioned (1), wherein, the frequency of described power supply at 1kHz in the scope between the 100kHz.
(3) as the manufacturing process of the magnetic recording media described in above-mentioned (1) or (2), wherein, described plasma is a glow discharge plasma.
(4) as the manufacturing process of any one the described magnetic recording media in above-mentioned (1) to (3), wherein, after forming described protective film, the surface of described protective film is handled, then form described lubricating layer with the described gas that is activated.
(5) as the manufacturing process of any one the described magnetic recording media in above-mentioned (1) to (4), wherein, described gas comprises the gas of at least a type of electing from the one group of gas that is made of nitrogen, oxygen and argon gas.
(6) as the manufacturing process of above-mentioned (1) any one described magnetic recording media in (5), wherein, be by between comparative electrode, applying an a kind of plasma that electric field produced near the described plasma that produces under the atmospheric air pressure.
(7) as the manufacturing process of above-mentioned (6) described magnetic recording media; wherein; described comparative electrode is set to spend miter angle from the inclined position 1 perpendicular to pending substrate, and in described pending substrate, described at least magnetosphere and protective film are formed on the described non-magnetic substrate.
(8) as the manufacturing process of above-mentioned (6) described magnetic recording media, wherein, described comparative electrode forms perpendicular to pending substrate, and in described pending substrate, described at least magnetosphere and protective film are formed on the described non-magnetic substrate.
(9) as the manufacturing process of above-mentioned (6) described magnetic recording media, wherein, by pending substrate being placed in come between the described comparative electrode described protective film is carried out surface treatment, in described pending substrate, on described non-magnetic substrate.
(10) as the manufacturing process of above-mentioned (1) any one the described magnetic recording media in (9); wherein; use the described gas that is activated that surface treatment is carried out on the two sides of described pending substrate simultaneously; in described pending substrate, described at least magnetosphere and protective film are formed on the described non-magnetic substrate.
(11) as the manufacturing process of any one the described magnetic recording media in above-mentioned (1) to (10), wherein, described non-magnetic substrate is a kind of substrate of electing from substrate of glass and silicon base.
(12) as the manufacturing process of above-mentioned (1) any one the described magnetic recording media in (10), wherein, in the described non-magnetic substrate, the thin film that is made of NiP or NiP alloy is formed on the surface of the substrate (base) that a kind of material of electing from Al, Al alloy, glass and silicon constitutes.
(13) a kind of magnetic recording media is according to the manufacturing process manufacturing of any one the described magnetic recording media in above-mentioned (1) to (12).
(14) a kind of magnetic recording and playback device are provided with magnetic recording media and the record and the magnetic head of playback of data on described magnetic recording media; Wherein said magnetic recording media is above-mentioned (13) described magnetic recording media.
(15) a kind of surface treatment devices; it has a function; thereby promptly under an approaching atmospheric air pressure, produce the gas that plasma formation is activated by between comparative electrode, applying an electric field; and make the gas radiation that is activated to the surface of pending substrate; in described pending substrate, one deck magnetosphere and layer protecting film layer are formed on the non-magnetic substrate at least.
Invention among the application and Japanese laid-open patent application, the similarity of publication number No.S62-150526 are, use plasma to improve the character of surface of described diaphragm.Yet, with the Japanese laid-open patent application, the technology of carrying out Cement Composite Treated by Plasma in a vacuum described in the publication number No.S62-150526 is opposite, and the very difference of the invention among the application is that Cement Composite Treated by Plasma is being carried out near under the atmospheric air pressure.If Cement Composite Treated by Plasma is carried out in a vacuum, because the processing gas that is activated contacts with the surface of described diaphragm under the situation of almost not losing its any activity, the part of described diaphragm self can be corroded.On the other hand; if used processing gas is being used Cement Composite Treated by Plasma near under the atmospheric air pressure, so because its high molecular density has frequent collision to take place between its molecule; therefore its active just reduction makes it be suitable for the surface treatment of described diaphragm.In addition, owing to comprise such as vacuum chamber, aspiration pump and from atmosphere and be pressed onto the transfer system that transmits the vacuum, the vacuum equipment that is used for carrying out in a vacuum Cement Composite Treated by Plasma is very big, and very expensive.On the other hand, be used in, do not need vacuum equipment, can make simplified equipment and reduce cost near in the situation of handling with plasma under the atmospheric air pressure.
In addition, in the manufacturing of described magnetic recording media, a step that generally includes is after having deposited diaphragm, to use such as liquid such as water, acid or alkali and clean to remove the dust on adhering in vacuum equipment.If carry out Cement Composite Treated by Plasma in a vacuum, finishing (modification) characteristic meeting serious degradation is because described diaphragm surface becomes wet in cleaning step subsequently.Prevent this point although must carry out Cement Composite Treated by Plasma after cleaning step, because this needs the another one vacuum equipment, cost will increase a lot.On the other hand, near carrying out in the situation of Cement Composite Treated by Plasma under the atmospheric air pressure,, do not need the change of equipping yet, so can not cause the increase of any cost even a cleaning step after, handle.
Description of drawings
Fig. 1 is a sectional view, has shown an embodiment of the magnetic recording media among the present invention;
Fig. 2 is a schematic block diagram, has shown an embodiment of the plasma generation unit of the magnetic recording media that is used for making the present invention;
Fig. 3 is a schematic block diagram, has shown another embodiment of the plasma generation unit of the magnetic recording media that is used for making the present invention;
Fig. 4 is a schematic block diagram, has shown another embodiment of the plasma generation unit of the magnetic recording media that is used for making the present invention;
Fig. 5 is a schematic block diagram, has shown another embodiment of the plasma generation unit of the magnetic recording media that is used for making the present invention;
Fig. 6 is a schematic block diagram, has shown another embodiment of the plasma generation unit of the magnetic recording media that is used for making the present invention.
Embodiment
Below with reference to accompanying drawing embodiments of the invention are given an explaination.
Fig. 1 is a sectional view, has shown an embodiment of the magnetic recording media among the present invention.
Magnetic recording media in the present embodiment applies one deck lubricant layer 6 then and forms by sequential cascade basalis 2, middle layer 3, magnetosphere 4 and protective film 5 on non-magnetic substrate 1 on uppermost one deck.
The examples of material that can be used for non-magnetic substrate 1 comprises, metal material such as aluminium and aluminium alloy, inorganic material is such as glass, pottery, titanium, carbon and silicon, and macromolecular compound such as polyethylene terephthalate (polyethylene terephthalate), polyimide (polyimide), polyamide (polyamide), polycarbonate (polycarbonate), polysulfones (polysulfone), poly-naphthalene ethene (polyethylene naphthalate), polyvinyl chloride (polyvinyl chloride) and circulation hydrocarbonaceous polyolefin (cyclic hydrocarbon-containing polyolefin).In addition, one or more films of from NiP, NiP alloy and other alloy, selecting can by electroplate or sputter or the like by vapour deposition on the surface of these substrates.
The material of described basalis 2 can be Cr or the Cr alloy that is made of Cr and one or more materials of selecting from Ti, Mo, Al, Ta, W, Ni, B, Si, Mn and V.
In basalis 2 situation for non-magnetic substrate layer with sandwich construction, at least one component layers that constitutes described non-magnetic substrate layer can constitute with above-mentioned Cr alloy or Cr.
Above-mentioned non-magnetic substrate layer also can be made of NiAl base alloy, RuAl base alloy or Cr alloy (alloy that is made of Cr and one or more materials of selecting from Ti, Mo, Al, Ta, W, Ni, B, Si, Mn and V).
Have in the situation of sandwich construction at the non-magnetic substrate layer, at least one component layers that constitutes described non-magnetic substrate layer can be made of NiAl base alloy, RuAl base alloy or above-mentioned Cr alloy.
The material in middle layer 3 is to use to help the epitaxially grown of Co alloy, and its preferably a kind of nonmagnetic substance with hep structure, Co are that the Co alloy of main raw material(s) is exactly this material.Preferred example comprises such material, wherein contains any material of electing from Co-Cr base alloy, Co-Cr-Ru base alloy, Co-Cr-Ta base alloy, Co-Cr-Zr base alloy.
Preferably a kind of material with hcp structure of the material of described magnetosphere 4 is that the Co alloy of main raw material(s) is exactly this material with Co.Preferred example comprises such material, wherein contains any material of electing from Co-Cr-Ta base alloy, Co-Cr-Pt base alloy, Co-Cr-Pt-Ta base alloy, Co-Cr-Pt-B base alloy and Co-Cr-Pt-B-Cu base alloy.
Material as described protective film 5 can be a kind of carbon-based material, such as amorphous carbon, hydrogen-containing carbon and fluorine-containing carbon, or a kind of ceramic based material, such as silica (silica) and oxidation Zirconium (zirconia).Specifically, preferably use hard and close CVD carbon, not only because its durability, also because its economy and productive rate height.Because if crossing to approach, the thickness of described protective film 5 will reduce its durability; if and its thickness blocked up will increase the record and playback during loss; so the thickness of protective film 5 is set to 10 to 150 dusts (1 to 15nm), be preferably set to 20 to 60 dusts (2 to 6nm).As hereinafter described, the gas (processing gas) that uses plasma to activate carries out surface treatment to protective film 5.
Uppermost lubricating layer 6 comprises a kind of condensate, and it is a kind of PFPE (perfluoropolyether) compound that contains polymerizable (polymerizeable) unsaturated group.The example that contains the per-fluoro polyether compound of polymerizable unsaturated group comprises the compound that organic group and at least one the terminal bonding as the PFPE of main chain by will containing polymerizable unsaturated bond gets up to constitute.
Magnetic recording among the present invention and playback device have been equipped with above-mentioned magnetic recording media, and this medium has protective film 5, have carried out surface treatment with above-mentioned processing gas thereon, also are equipped with magnetic head and write down and playback of information on described magnetic recording media.
To explain an example of magnetic recording media manufacturing process of the present invention below.
At first; on non-magnetic substrate 1, form after basalis 2, middle layer 3, magnetosphere 4 and the protective film; the gas that uses plasma to activate carries out surface treatment and forms protective film 5 on protective film, wherein plasma is to produce being about under the atmospheric air pressure.Then, on this protective film 5, form lubricating layer 6.Above-mentioned plasma is preferably glow discharge plasma.
Here be used for carrying out the surface-treated surface treatment devices and can use a kind of plasma generation unit, this plasma generation unit can produce stable plasma under approaching atmospheric air pressure, it uses sinusoidal wave high frequency electric source as the power supply that produces plasma.
The available devices example comprises atmospheric plasma finishing device (Esquare) and atmospheric pressure plasma cleaning head (Matsushita Electric Works).
Be meant 1.3 * 10 near atmospheric air pressure
4To 13 * 10
4The air pressure of Pa.Specifically, preferably use 9.9 * 10
4To 10.3 * 10
4The approaching atmospheric air pressure of pa is because it can make things convenient for pressure to regulate and simplify the formation of described device.
Utilize Fig. 2 to explain plasma generation unit used in the present embodiment below.
Plasma generation unit among Fig. 2 mainly by a pair of electrode of opposite plate (comparative electrode) 21a and 21b, one be used in the gas access 22 that gas is provided between battery lead plate 21a and the 21b, a plasma generation power supply 23 and a substrate holder that is used for fixing pending substrate 25 26 that applies electric field between described comparative electrode constitutes.
Pending substrate 25 have at least be formed on one on the non-magnetic substrate one deck magnetosphere and do not have surface treated protective film; in the situation of present embodiment, have be formed on one on the non-magnetic substrate 1 basalis 2, middle layer 3, magnetosphere 4 and do not have surface treated protective film.
Described plasma generation unit has a function, promptly near forming the gas of activation by apply a plasma that electric field produced between a pair of comparative electrode 21a and 21b under the atmospheric air pressure, and the gas radiation that makes activation is to the surface of pending substrate 25.
The material of each battery lead plate uses iron, copper, aluminium or its alloy.Although the distance between the described comparative electrode is preferably 0.1 to 50mm, consider the stability of plasma discharge, this distance is more preferably gets 0.1 to 5mm.
Preferred one deck dielectric material that covers on each electrode.Cover each electrode with dielectric material and can prevent to constitute the metal of electrode by plasma oxidation and nitrogenize.Preferred a kind of oxide such as the aluminium oxide (Al of using
2O
3) be used as the dielectric material material.
Between battery lead plate 21a and 21b, apply electric field with a high_frequency sine wave.Consider the stability of plasma discharge, preferably using sinusoidal wave frequency is 1 to 100kHz, particularly 10 arrives 50kHz.
In the present invention, use sinusoidal wave benefit to introduce below.
If relatively sine wave and pulsating wave need increase crest voltage when using pulsating wave, because it is lower to be generally used for the dutycycle of pulsating wave of plasma discharge.For example, the used normal condition of plasma discharge comprises frequency 10kHz, pulse width 10 microseconds (dutycycle 10%), crest voltage 30000V.On the other hand, in the situation of sine wave, crest voltage can reduce, although because waveform is sinusoidal wave, voltage application is continuous.Crest voltage was 10000V when for example, frequency was 10kHz.
Although the relation between crest voltage and the corrosion is not entirely understood, imagine that easily the possibility that higher crest voltage makes low baking temperature flower discharge (micro-arcing) take place probably increases.Although corrosion has an a variety of causes, what generally known is if form pitting in diaphragm, finally to be diffused on the surface of diaphragm from these holes in substrate and contained Ni, Li, Na, the Co or the like of magnetosphere so.If the discharge of low baking temperature flower takes place, in diaphragm, form pitting so, believe that this can cause the generation of corroding conversely.
In using the situation of high_frequency sine wave, preferably between the power supply of the electrode of load end and power end, carry out impedance matching.If impedance does not match, can produce reflection wave, cause job insecurity and increase the possibility that the low baking temperature flower discharges.
According to the type of reacting gas (nitrogen, oxygen, argon gas or its potpourri) or the material and the size of pending substrate, the impedance meeting generation fluctuation of electrode tip.In this case, use the PLL circuit, the oscillation frequency by allowing power end changes according to the variation of electrode tip impedance, and impedance is mated.In addition, the PLL circuit is meant phaselocked loop, is used to produce a phase locked new signal with the signal of certain frequency, and it is a kind of technology that makes high-frequency circuit stable operation.
The gas that provides between battery lead plate 21a and 21b preferably uses nitrogen, oxygen, argon gas or its potpourri.Because very big at the gas flow that is consumed when using under the atmospheric air pressure, so, the mixed gas of cheap nitrogen, oxygen or nitrogen and oxygen more preferably used.
Among Fig. 2, before carrying out surface treatment (pending substrate 25), pair of electrodes plate 21a and 21b settle perpendicular to protective film.Although plasma generation is between described electrode, because the plasma that is produced is to external diffusion, so plasma has also produced plasmoid from the place that sheds between the described electrode.Be preferably 0.1 to 5mm from an end of described comparative electrode plate to the distance the protective film (pending substrate 25).If this distance is less than 0.1mm, pending substrate 25 has the danger that is crashed through by battery lead plate, does not therefore wish that this distance is too little.If this distance surpasses 5mm, because plasma excessively scatters, make effect reduce a lot, so just can not obtain surface treatment effect.Near offer the gas between pair of electrodes plate 21a and the 21b under the atmospheric air pressure between these electrodes because the activation of the plasma that quilt is produced becomes processing gas; because this processing gas has high molecular density; owing to the generation of intermolecular frequent impact makes active decline, therefore make it be suitable for the surface treatment of diaphragm.
A kind of transfer approach that does not contact two surfaces of described substrate of preferred use is so that can use the two sides of magnetic recording media (disk).Therefore, preferably transmit pending substrate 25 by clamping inner edge or outer rim.Transfer rate is preferably 10 to 6000mm/ minute.Consider high output and surface treatment effect, transfer rate more preferably 100 to 3000mm/ minute.Transfer approach can comprise mobile pending substrate 25 or mobile plasma generation unit.The example that moves the transfer approach of pending substrate 25 has, and moves pending substrate 25 by using substrate holder 26, and this substrate holder has a function, and this function can move up and down it, the surface of body sequential processes protective film so that the energy use is regulated the flow of vital energy.
As shown in Figure 3, in order to use two surfaces of magnetic recording media, preferably settle the plasma generation unit as previously described like that, and the gas that plasma activated that is used near generation under the atmospheric air pressure carries out surface treatment to the two sides of pending substrate 25 on the two sides of pending substrate 25.
In the situation that the inner edge or the outer rim of the pending substrate 25 by clamping transmits, the inner edge of pending substrate 25 or outer rim are finally covered by the shade of carriage 26, cause being had by the place's of covering surface treatment effect the danger of reduction.In order to prevent this point, preferably, described relative pair of electrodes plate 21a and 21b are set to respect to the angle of the protective film before the surface treatment (pending substrate 25) from upright position inclination 1 to 45 degree, as shown in Figure 4.In addition, shown among Fig. 4 that the outer rim of pending substrate 25 by clamping transmits the example of its device.
If a pair of comparative electrode plate 21a and 21b are set to from the angle of upright position inclination 1 to 45 degree with respect to pending substrate 25; carry out the surface-treated words then; because plasma is with respect to diaphragm radiation at a slant, the processing gas that is activated by plasma also can touch by the part that shade covered of carriage 26.In this case, also preferably settle the plasma generation unit, as shown in Figure 5 on the two sides of pending substrate 25.
Protective film in the pending substrate 25 also can by make pending substrate 25 between described a pair of comparative electrode plate 21a and the 21b by carrying out surface treatment, as shown in Figure 6.In this case, can carry out stronger surface treatment, because the density of plasma is higher.
[example 1 is to example 17]
Be coated with the NiP film aluminum alloy substrate (diameter: 95mm, internal diameter: 25mm, thickness: 1.27mm) fully clean and drying after, (CSS district) it is carried out radiation highly is the projection of 10nm with formation from radius 17mm to 19mm with laser.Subsequently, described substrate be placed on a direct current magnetron sputtering system (the C3010 type, Anelva) in.Air is extracted into can reach 2 * 10
-7Torr (2.7 * 10
-5Pa) after the vacuum, described substrate is heated to 250 ℃.
After the heating, utilizing the target of being made up of Cr to come stacked thickness is the non-magnetic substrate layer of 5nm.In addition, (Cr:80at%, Mo:20at%) the folded thickness of the target layer of Zu Chenging is the non-magnetic substrate layer of 5nm by the Cr-Mo alloy in utilization.Then, (Co:65at%, Cr:35at%) the folded thickness of the target layer of Zu Chenging is the nonmagnetic intermediate layer of 2nm by the Co-Cr alloy in utilization.Then; utilization is by Co-Cr-Pt-B alloy (Co:60at%; Cr:22at%; Pt:12at%; B:6at%) target that constitutes form thickness be the magnetosphere of CoCrPtB alloy-layer form of 20nm as magnetosphere, and utilize the stacked thickness of plasma CVD system to obtain a pending substrate for the diaphragm that constitutes by CVD carbon of 5nm.The pressure of argon gas is set to 6mTorr (0.8Pa) during thin film deposition.Deposited after the diaphragm, described substrate is removed from vacuum system, utilizes spinner to clean and drying with pure water.Subsequently, adopt atmospheric plasma finishing unit (Esquare) surface treatment to be carried out in mode shown in Figure 2 in the diaphragm surface of pending substrate as the plasma generation unit.With sinusoidal wave high frequency electric source as the plasma generation power supply.This power supply output is set to 1kw.Because this surface treatment devices is equipped with the PLL circuit, fluctuation can take place to prevent resonance in frequency.Therefore, sine wave freuqency is controlled as 12 to 17kHz.Transfer rate, nitrogen flow rate, oxygen gas flow rate, the variation from the end (from the nearest end of pending substrate) of comparative electrode to the distance of pending suprabasil diaphragm are shown in table 1.
Measure the contact angle of these samples with a water contact meter (water contact gauge).These the results are shown in table 1.
After above-mentioned surface treatment, the lubricant that is made of PFPE is coated onto on the described diaphragm with the draw rate (pulling rate) of the method for dipping with 3mm/sec after adjusting to percentage by weight 0.05%, to obtain disk (sample).In addition, fluorine-based solvent AK225 (Asahi Glass) during this time is used as solvent.
[comparative example 1]
In addition, except not carrying out on the protective film the above-mentioned surface treatment,, be used for comparing to make a sample with the same mode of said method.
Thickness with the lubricant film on each sample of FTIR measurement manufacturing.These the results are shown in table 1.In addition, measure the bonding ratio with the mode that describes below, as the index of bond strength between lubricant layer and the protective film.Cleaned in 15 minutes after the surface of above-mentioned disk by immersing fluorine-based solvent AK225 (Asahi Glass), be to measure before the flushing with FTIR on the position at 20mm place and the thickness of lubricant layer afterwards at radius, the thickness of getting lubricant layer after the flushing than the thickness of lubricant layer before the flushing as bonding than (%).These the results are shown in table 1.
Also measured kinetic friction coefficient.In temperature is that 25 ℃, humidity are to have carried out CSS (contact start and stop) durability test under the condition of 60%RH.In this test, with a css test device and reference MR head (DLC coating, 30% slide block as magnetic head, load: 2.5g) carry out 10 in the CSS district, 000 CSS operation (comprising that with 10 rotational speed of 000rpm (keeping 1 second) and stop (1 second) was with 5 seconds intervals repetition).The kinetic friction coefficient of magnetic disk surface is shown in table 1 after 10,000 CSS operations.
Also measured coefficient of static friction.In temperature is that 25 ℃, humidity are to have carried out CSS (contact start and stop) durability test under the condition of 60%RH.In this test, with a css test device and reference MR head (DLC coating, 30% slide block as magnetic head, load: 2.5g) carry out 10 in the CSS district, 000 CSS operation (comprising that with 10 rotational speed of 000rpm (keeping 1 second) and stop (1 second) was with 5 seconds intervals repetition).The coefficient of static friction of magnetic disk surface is shown in table 1 after 10,000 CSS operations.
Also tested film thickness reduction rates (revolve and fly test).Disk in 80 ℃ environment with 10, the rotational speed of 000rpm 72 hours.Before this operation and measure the thickness of a locational lubricant layer at radius 20mm place afterwards, measure before the test and the reduction rate of lubricant layer thickness afterwards with FTIR.These the results are shown in table 1.
In addition, although shown in the unit of lubricant film thickness value be dust, on duty with 0.1 by these of lubricant film thickness shown in will showing, they can be converted into the nanometer is the value of unit.Also carried out corrosion test.Sample was placed 96 hours in 80 ℃ of temperature and humidity 85%RH.Also count the number of Staining with the surface of microscopic examination sample.Observe 1 micron or bigger foreign matter on whole surface, these foreign matters be can be regarded as Staining.In addition, the surface of confirmatory sample does not have 1 micron or bigger foreign matter before carrying out corrosion test.
[comparative example 2 to 4]
In the mode identical pending suprabasil protective film is carried out surface treatment with atmospheric plasma finishing unit (Sekisui Chemical) with example 1.Use the pulse power as the power supply that produces plasma.Frequency setting is 30kHz, and pulse width is set at 10 microseconds.Other treatment conditions are identical with example 1.Transfer rate, nitrogen flow rate, oxygen gas flow rate, the variation from the end (from the nearest end of pending substrate) of comparative electrode to the distance of pending suprabasil diaphragm are shown in table 1.
Table 1
| Transfer rate | Nitrogen flow rate | Oxygen gas flow rate | The comparative electrode end is to the distance of diaphragm | Contact angle | Lubricant film thickness | The bonding ratio | Kinetic friction coefficient | Coefficient of static friction | The thickness reduction rate | Staining | |
| mm/min | l/min | ml/min | mm | Degree | | ％ | ％ | No. | |||
| Example 1 | 500 | 40 | 10 | 2 | 5.6 | 20.6 | 71 | 0.34 | 0.42 | 2 | 6 |
| Example 2 | 1000 | 40 | 10 | 2 | 10.3 | 20.5 | 73 | 0.37 | 0.43 | 3 | 4 |
| Example 3 | 2000 | 40 | 10 | 2 | 11.6 | 20.7 | 74 | 0.33 | 0.41 | 4 | 2 |
| Example 4 | 4000 | 40 | 10 | 2 | 12.7 | 20.1 | 72 | 0.31 | 0.47 | 6 | 0 |
| Example 5 | 2000 | 40 | 10 | 1 | 9.4 | 20.9 | 71 | 0.34 | 0.41 | 2 | 1 |
| Example 6 | 2000 | 40 | 10 | 3 | 11.2 | 20.1 | 74 | 0.36 | 0.43 | 3 | 2 |
| Example 7 | 2000 | 40 | 10 | 5 | 14.5 | 19.6 | 70 | 0.32 | 0.50 | 5 | 5 |
| Example 8 | 2000 | 40 | 10 | 10 | 17.3 | 18.3 | 61 | 0.34 | 0.55 | 12 | 0 |
| Example 9 | 2000 | 1 | 10 | 2 | 20.4 | 18.4 | 57 | 0.35 | 0.71 | 11 | 0 |
| Example 10 | 2000 | 10 | 10 | 2 | 17.2 | 18.5 | 64 | 0.37 | 0.66 | 9 | 0 |
| Example 11 | 2000 | 20 | 10 | 2 | 14.3 | 19.4 | 67 | 0.31 | 0.61 | 8 | 0 |
| Example 12 | 2000 | 100 | 10 | 2 | 7.8 | 20.6 | 75 | 0.34 | 0.41 | 5 | 4 |
| Example 13 | 2000 | 200 | 10 | 2 | 6.4 | 20.7 | 78 | 0.33 | 0.45 | 4 | 2 |
| Example 14 | 2000 | 40 | 0 | 2 | 25.4 | 18.2 | 54 | 0.36 | 0.41 | 4 | 0 |
| Example 15 | 500 | 40 | 0 | 2 | 10.4 | 20.1 | 75 | 0.31 | 0.44 | 4 | 0 |
| Example 16 | 2000 | 40 | 20 | 2 | 7.8 | 20.4 | 70 | 0.37 | 0.43 | 5 | 3 |
| Example 17 | 2000 | 40 | 40 | 2 | 6.4 | 20.6 | 72 | 0.39 | 0.40 | 3 | 2 |
| Comparative example 1 | No Cement Composite Treated by Plasma | 44.7 | 17.3 | 41 | 0.31 | 1.30 | 17 | 0 | |||
| Comparative example 2 | 600 | 40 | 0 | 2 | 3.8 | 20.2 | 69 | 0.39 | 0.50 | 3 | 481 |
| Comparative example 3 | 1000 | 40 | 0 | 2 | 3.9 | 20.7 | 72 | 0.34 | 0.51 | 5 | 394 |
| Comparative example 4 | 600 | 40 | 0 | 5 | 10.1 | 18.6 | 57 | 0.35 | 0.78 | 8 | 97 |
As what seen from result shown in the table 1, owing to carried out Cement Composite Treated by Plasma, contact angle is reduced to 5.6-25.4 degree (example 1 to 17) significantly from 44.7 degree (comparative example 1).Along with the reduction of contact angle, bonding is than bringing up to 54-78% (example 1 to 17) significantly from 41% (comparative example 1).This means, moved freely the decreased number of molecule in the lubricant, so coefficient of static friction is improved to 0.40-0.71 (example 1 to 17) significantly from 1.30 (comparative examples 1), and from revolve fly the test determined thickness slip also be improved to 2-12% significantly from 17% (comparative example 1).In addition, determine in these examples that when an end of comparative electrode during to the distance increase of diaphragm, contact angle also increases.
In these examples,, do not observe the surface-treated effect if an end of comparative electrode is 10mm to the distance of protective film.
In addition, although do not observe Staining (comparative example 1),, can observe Staining 100 to 500 magnitude (comparative example 2 to 4) if use atmospheric plasma finishing unit if do not carry out Cement Composite Treated by Plasma.On the other hand, sinusoidal wave if employed atmospheric plasma finishing unit uses, can observe, the number of Staining significantly is reduced to 0 to 6 spot (example 1 to 17).
Based on The above results; owing to adopted sinusoidal wave atmospheric plasma finishing unit protective film being carried out plasma surface treatment near under the atmospheric air pressure; find that contact angle has had remarkable improvement, the result has also observed the adhering improvement of lubricant.As a result, not only coefficient of static friction fully reduces, and flies phenomenon owing to prevented to revolve, and start-up operation is improved and durability is strengthened, and has obtained gratifying surface lubrication characteristic.In addition, can also obtain having the magnetic recording media of satisfied corrosive property.
According to the manufacturing process of magnetic recording media of the present invention, can produce a kind of magnetic recording media, it has outstanding start-up operation and durability, gratifying surface lubrication and remarkable corrosive property.
Magnetic recording media of the present invention has outstanding start-up operation and durability, gratifying surface lubrication and remarkable corrosive property.
Claims (15)
1. the manufacturing process of a magnetic recording media, be included on the non-magnetic substrate sequential cascade one deck magnetosphere, layer protecting film layer and one deck lubricating layer at least, and come described protective film is carried out surface treatment with the gas that plasma activated that produces down near an atmospheric air pressure; Wherein,
Use sinusoidal wave high frequency electric source as the power supply that produces described plasma.
2. the manufacturing process of magnetic recording media according to claim 1, wherein, the frequency of described power supply at 1kHz in the scope between the 100kHz.
3. the manufacturing process of magnetic recording media according to claim 1, wherein, described plasma is a glow discharge plasma.
4. the manufacturing process of magnetic recording media according to claim 1 wherein, is handled the surface of described protective film with the described gas that is activated after forming described protective film, then forms described lubricating layer.
5. the manufacturing process of magnetic recording media according to claim 1, wherein, described gas comprises the gas of at least a type of electing from the one group of gas that is made of nitrogen, oxygen and argon gas.
6. the manufacturing process of magnetic recording media according to claim 1 wherein, is being by apply a plasma that electric field produced between comparative electrode near the described plasma that produces under the atmospheric air pressure.
7. the manufacturing process of magnetic recording media according to claim 6; wherein; described comparative electrode is set to spend miter angle from the inclined position 1 perpendicular to pending substrate, in described pending substrate, is formed with described magnetosphere and protective film at least on described non-magnetic substrate.
8. the manufacturing process of magnetic recording media according to claim 6, wherein, described comparative electrode forms perpendicular to pending substrate, in described pending substrate, is formed with described magnetosphere and protective film at least on described non-magnetic substrate.
9. the manufacturing process of magnetic recording media according to claim 6; wherein; by pending substrate being placed in come between the described comparative electrode described protective film is carried out surface treatment; in described pending substrate, on described non-magnetic substrate, be formed with described magnetosphere and protective film at least.
10. the manufacturing process of magnetic recording media according to claim 1; wherein; the gas that use is activated carries out surface treatment simultaneously to the two sides of pending substrate, in described pending substrate, is formed with described magnetosphere and protective film at least on described non-magnetic substrate.
11. the manufacturing process of magnetic recording media according to claim 1, wherein, described non-magnetic substrate is a kind of substrate of electing from substrate of glass and silicon base.
12. the manufacturing process of magnetic recording media according to claim 1, wherein, in the described non-magnetic substrate, the thin film that is made of NiP or NiP alloy is formed on the surface of the substrate that a kind of material of electing from Al, Al alloy, glass and silicon constitutes.
13. a magnetic recording media is by the manufacturing process manufacturing of the described magnetic recording media of claim 1.
14. magnetic recording and playback device are provided with magnetic recording media and the magnetic head of record and playback of data on described magnetic recording media; Wherein said magnetic recording media is a magnetic recording media according to claim 13.
15. surface treatment devices; it has a function; promptly near producing the gas that plasma and then formation are activated by between comparative electrode, applying an electric field under the atmospheric air pressure; and make this gas radiation that is activated to the surface of pending substrate; in described pending substrate, on non-magnetic substrate, be formed with one deck magnetosphere and layer protecting film layer at least.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP239570/2004 | 2004-08-19 | ||
| JP2004239570 | 2004-08-19 | ||
| JP094386/2005 | 2005-03-29 |
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| Publication Number | Publication Date |
|---|---|
| CN101015003A true CN101015003A (en) | 2007-08-08 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 200580027949 Pending CN101015003A (en) | 2004-08-19 | 2005-08-17 | Magnetic recording medium and production process thereof |
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| CN (1) | CN101015003A (en) |
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- 2005-08-17 CN CN 200580027949 patent/CN101015003A/en active Pending
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